1. Field of the Invention
The invention relates to reinforced structural elements including a member of fibre reinforced material. Examples of such fibre reinforced materials are glass fibre reinforced concrete or glass fibre reinforced gypsum, or gypsum or concrete reinforced with stainless steel fibres.
The use of such fibre reinforced materials is advantageous in that the strength and wear resistance of such materials are superior to unreinforced materials. This allows the dimensions of structural elements formed from such materials to be thinner and lighter than similar elements made of unreinforced materials. Further, it allows elements to be constructed from such materials which, because of weight and size considerations, could not be constructed from unreinforced materials.
2. Brief Review of the Prior Art
An example of this is a water drainage channel. Such channels have conventionally been made of unreinforced concrete and are formed of sections laid end to end and embedded in a concrete surround. Unreinforced concrete channel sections are necessarily thick and heavy and require mechanical lifting gear to handle them. In principle, channel sections of, say, glass reinforced concrete, could be made sufficiently thin and light to be handled by without mechanical lifting gear.
However, when used with a concrete surround, fibre reinforced materials such as glass fibre reinforced concrete can have the disadvantage that they flex and bend and plainly this is unacceptable. It has been proposed, in order to overcome this problem, to make such structural members with two spaced layers of glass fibre reinforced material with a void between the layers filled with an expanded plastics material, such as expanded polystyrene. It has been found, however, that such composite members are liable to fail and for this reason, in some applications, the use has been banned.